Sunday, September 19, 2004

Alpharma and gabapentin

Alpharma stated on September 17, 2004 that the CAFC had set aside its earlier order that had prevented the company from selling a generic capsule form of Neurontin (gabapentin). Neurontin is one of Pfizer's biggest products with annual sales approaching $3 billion.

We had discussed issues with gabapentin in the context of the Warner-Lambert/Apotex case in the March 2003 issue of Intellectual Property Today ("It's bound to scare you, boy"):

In the realm of Hatch-Waxman, Warner-Lambert sued Apotex, (2003 U.S. App. LEXIS 594. )asserting that the generic's version of the drug would infringe a patent that of Warner-Lambert for a method of using gabapentin to treat certain neurodegenerative diseases such as stroke, although the FDA had approved gabapentin only for treatment of epilepsy. The Federal Circuit decision makes clear that such an approach by the innovator drug company does not even state a cause of action against the generic company under the Hatch-Waxman Act:

Warner-Lambert does not have a cause of action under ยง 271(e)(2)(A). Congress clearly intended to limit actions for infringement of method-of-use patents under ยง 271(e)(2)(A) to "controlling use patents," or patents that claim an approved use of a drug. An ANDA applicant, who necessarily "piggybacks" on the approved NDA of the innovator, can only apply to sell the approved drug, which, in this case, is no longer under patent, and to market it for the use for which the FDA has indicated that the drug is safe and efficacious, for which use the patent here has also expired. Apotex has neither submitted an application to sell a drug claimed in an extant patent, nor submitted an application to sell a drug the use of which is claimed in an extant patent. Both gabapentin and its only FDA-approved use are now off-patent. [end case quote]

Separately, the Federal Circuit also found no induced infringement under 271(b). Although an NDA, and hence an ANDA, only approves a use for which safety and efficacy have been proven, a physician may prescribe an approved drug for any use consistent with acceptable medical practice. Warner-Lambert stated that, by 1998, only about 22% of gabapentin sales were for treatment of epilepsy, the remaining 78% being prescribed for off-label uses, including the infringing use of treating neurodegenerative diseases. The Federal Circuit stated precedent holds that mere knowledge of possible infringement by others does not amount to inducement and specific intent and action to induce infringement must be proven. The court also noted that intent to induce infringement cannot be inferred even when the defendant has actual knowledge that some users of its product may be infringing the patent. The court also invoked logic: it defies common sense to expect that Apotex will actively promote the sale of its approved gabapentin, in contravention of FDA regulations, for a use that (a) might infringe Warner- Lambert's patent and (b) constitutes such a small fraction of total sales.



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